Method for performing D2D operation in wireless communication system, and terminal using same

Abstract

Provided are a method for performing device-to-device (D2D) operation of a terminal in a wireless communication system, and a terminal using the same. The method is characterized by applying frequency synchronization on the basis of a primary cell of a first frequency, applying time synchronization on the basis of a non-serving cell of a second frequency for which D2D operation is to be performed, and performing the D2D operation on the basis of the frequency synchronization and the time synchronization.

What is claimed is: 
     
       1. A method of transmitting a device-to-device (D2D) discovery signal in a wireless communication system, the method performed by a user equipment (UE) and comprising:
 receiving, from a base station on a first carrier having a first frequency, D2D configuration information, the D2D configuration information including reference carrier information; and 
 based on the D2D configuration information, transmitting, on a second carrier having a second frequency, the D2D discovery signal, 
 wherein the second carrier and second frequency are different from the first carrier and the first frequency, respectively, 
 wherein the reference carrier information indicates a third carrier different from the second carrier and having a third frequency different from the second frequency, 
 wherein the third carrier is one of plural carriers used for the communication between the UE and the base station, the plural carriers further including the first carrier, and 
 wherein the third carrier is used as reference for downlink measurements and synchronization related to transmission of D2D discovery signal on the second carrier. 
 
     
     
       2. The method of  claim 1 , wherein the third carrier is a carrier linked to the second carrier via system information. 
     
     
       3. The method of  claim 1 , wherein the third carrier is a carrier not linked to the second carrier via system information. 
     
     
       4. The method of  claim 1 , wherein the second carrier is configured separately from the first carrier. 
     
     
       5. The method of  claim 1 , wherein the third carrier is the first carrier. 
     
     
       6. The method of  claim 1 , wherein the third carrier is different from the first carrier. 
     
     
       7. A user equipment (UE) comprising:
 a transceiver for transmitting and receiving a radio signal; and 
 a processor coupled to the transceiver, wherein the processor is configured to: 
 receive, from a base station on a first carrier having a first frequency, D2D configuration information, the D2D configuration information including reference carrier information; and 
 based on the D2D configuration information, transmit, on a second carrier having a second frequency, the D2D discovery signal, 
 wherein the second carrier and second frequency are different from the first carrier and the first frequency, respectively, 
 wherein the reference carrier information indicates a third carrier different from the second carrier and having a third frequency different from the second frequency, 
 wherein the third carrier is one of plural carriers used for the communication between the UE and the base station, the plural carriers further including the first carrier, and 
 wherein the third carrier is used as reference for downlink measurements and synchronization related to transmission of D2D discovery signal on the second carrier. 
 
     
     
       8. The UE of  claim 7 , wherein the third carrier is a carrier linked to the second carrier via system information. 
     
     
       9. The UE of  claim 7 , wherein the third carrier is a carrier not linked to the second carrier via system information. 
     
     
       10. The UE of  claim 7 , wherein the second carrier is configured separately from the first carrier. 
     
     
       11. The UE of  claim 7 , wherein the third carrier is the first carrier. 
     
     
       12. The UE of  claim 7 , wherein the third carrier is different from the first carrier.